The present invention relates generally to exterior mounted rear view mirrors for motor vehicles and, more specifically, to rear view mirrors having indicators incorporated into the mirror.
It is highly desirable to provide adjacent vehicles with information concerning a vehicle operator's intentions. Vehicles are required to include such indicators as brake lights, turn signals and hazard indicators. Turn signals, for example, are commonly mounted only on the very front and rear portions of the vehicle. In many instances a driver in a second vehicle adjacent to a first vehicle may not be able to adequately view the turn signals of the first vehicle due to his relative position to the front and rear of the first mentioned vehicle.
Providing additional information to adjacent vehicles has been the subject of several patents. One of my commonly assigned earlier patents, U.S. Pat. No. 5,436,741 uses a holographic film coupled to a mirror surface. An incandescent bulb placed within the mirror housing shines through a hologram. One problem with signal mirrors using an incandescent light source is that incandescent light sources generate a large quantity of heat. A sufficient amount of space must be left around the light source so that heat may be dissipated within the mirror housing without causing overheating. Overheating may cause damage to the mirror assembly or reduce the life of the signaling apparatus. Such a configuration is not suitable for applications requiring thin mirror housings.
Another known type of signal mirror replaces the incandescent light source with light emitting diodes to evenly distribute the light over an indicator area. A series of light reflectors are placed behind each of the diodes. Between the diodes and the indicator surface a light diffuser is used to help spread the light over the indicator surface. Light emitted from the diodes shine directly through the mirror in much the same manner as an incandescent light source. Commonly the light emitting diodes used generate a significant amount of heat. To properly spread the light pattern, the light emitting diodes must be spaced a pre-determined distance from the light diffuser. Also, space must be left for the light reflectors which are typically formed of a metallic material to reflect the light from the light emitting diodes. Such a configuration also has a package depth which is too deep for some mirror applications.
It would therefore be desirable to provide an indicator mirror having a reduced package depth that may be easily incorporated into a mirror housing.